Ⅰ 如何看c語言標准庫函數的源代碼
1、首先標准只是規定了這些函數的介面和具體的運行效率的要求，這些函數具體是怎麼寫得要看各個編譯器的實現和平台。
2、例如使用的編譯器是visual studio，微軟提供了一部分C運行時(CRT)的源碼，裡面會有memcpy，strcpy之類的函數的實現，在visual studio 2005下的路徑是C:Program FilesMicrosoft Visual Studio 8VCcrtsrc。
Ⅱ 在哪裡可以找到C語言標准庫的實現源代碼
Linux下的glic庫的源碼鏈接：
http://ftp.gnu.org/gnu/glibc/，你可以下載最新版本的glibc-2.24.tar.gz這個壓縮文件，在Windows系統下直接用WinRAR解壓即可，如果在Linux系統下用命令行解壓的話，命令如下：tar -xzvf glibc-2.24.tar.gz。
Ⅲ 急求C語言編寫的圖書管理系統源代碼，具體要求如下
/*這有個以前用過的程序，你可以自己改改使用，但是有些功
能好像有問題，會中斷運行。至於程序的縮進式格式就你自己
敲回車和退格解決吧，不然代碼看起來會很亂不好看。*/
#include<stdio.h>
#include<string.h>
#include<conio.h>
#include<stdlib.h>
#include<ctype.h>
#define STACK_INIT_SIZE 10
#define OK 1
#define TRUE 1
#define FALSE 0
#define ERROR 0
struct student /*定義學生類型，用於存放借出的書籍*/
{
int carnum;
char lendbook[10];
}student[1000];
struct employ /*定義職工類型*/
{
int employnum;
char employname[15];
int employage;
char employsex[2];
char employleve[10];
long int employtage;
}employ[50];
struct book /*定義書的類型*/
{
int booknum;
char bookname[10];
char bookcreat[10];
int turefalse; /*用於借書和還書模塊判斷一本書是否借出的條件*/
}book[1000];
struct car /*借書卡的數據類型*/
{
int carnum;
char studentname[10];
int studentclass;
}car[100];
huanbook() /*還書函數*/
{
FILE *fp,*fp2; /*定義兩個文件指針，fp2用於修改數據時設立臨時文件用，防止數據遭破壞*/
int i,n;
int carnum;
char lendbook[10];
printf("請你輸入你的卡號\n");
scanf("%d",&carnum);
fp=fopen("car.txt","r"); /*讀取卡號記錄*/
for(i=0;fread(&car[i],sizeof(struct car),1,fp)!=0;i++) /*for循環判斷卡號是否存在*/
{
if(car[i].carnum==carnum) /*卡號存在，進入下一循環*/
{
n=i;
fclose(fp);
printf("請輸入你要還的書的名字\n");
scanf("%s",lendbook);
fp=fopen("record.txt","r");
for(i=0;fread(&student[i],sizeof(struct student),1,fp)!=0;i++) /*判斷是否借閱了輸入的書*/
{
if(strcmp(student[i].lendbook,lendbook)==0) /*借閱了該書，進入下一循環，否則出錯顯示*/
{
fclose(fp);
fp=fopen("record.txt","r");
fp2=fopen("bookl.txt","w");
for(i=0;fread(&student[i],sizeof(struct student),1,fp)!=0;i++)
{
if(strcmp(student[i].lendbook,lendbook)==0)
{
continue; /*刪除還掉的書的借書記錄*/
}
fwrite(&student[i],sizeof(struct student),1,fp2); /*寫入原來沒還的書的記錄*/
}
fclose(fp);
fclose(fp2);
fp=fopen("record.txt","w");
fp2=fopen("bookl.txt","r");
for(i=0;fread(&student[i],sizeof(struct student),1,fp2)!=0;i++)
{
fwrite(&student[i],sizeof(struct student),1,fp); /*將借書記錄信息寫回*/
}
fclose(fp);
fclose(fp2);
fopen("bookl.txt","w"); /*清臨時文件的記錄*/
fclose(fp2);
fp=fopen("book.txt","r");
fp2=fopen("bookl.txt","w");
for(i=0;fread(&book[i],sizeof(struct book),1,fp)!=0;i++) /*將書的記錄寫入臨時文件，防止因為修改信息破壞以前的記錄*/
{
if(i==n)
{
book[i].turefalse=1;
fwrite(&book[i],sizeof(struct book),1,fp2); /*將還的書的原來狀態設為無人借閱的*/
continue;
}
fwrite(&book[i],sizeof(struct book),1,fp2);
}
fclose(fp);
fclose(fp2);
fp=fopen("book.txt","w");
fp2=fopen("bookl.txt","r");
for(i=0;fread(&book[i],sizeof(struct book),1,fp2)!=0;i++)
{
fwrite(&book[i],sizeof(struct book),1,fp); /*將臨時文件寫回*/
}
fclose(fp);
fclose(fp2);
fopen("bookl.txt","w"); /*清臨時文件*/
fclose(fp2);
printf("還書完畢，按任意鍵返回\n");
getch();
return 1;
}
}
printf("你沒有借這樣的書，任意鍵返回\n"); /*出錯提示*/
fclose(fp);
getch();
return 0;
}
}
printf("系統沒這樣的卡，和管理員聯系,按任意鍵返回\n"); /*出錯提示*/
fclose(fp);
getch();
}
findbook()
{
FILE *fp;
char bookname[10];
int ture,i;
fp=fopen("book.txt","r");
printf("請輸入你要查找的書名\n");
scanf("%s",bookname);
for(i=0;fread(&book[i],sizeof(struct book),1,fp)!=0;i++)
{
if(strcmp(bookname,book[i].bookname)==0)
{
if(book[i].turefalse==1)
{
printf("這本書的詳細資料是：%d %s %s 此書現在無人借閱\n按任意鍵返回\n",book[i].booknum,book[i].bookname,book[i].bookcreat);
}
else {printf("這本書已經有人借出\n");fclose(fp);return 0;}
fclose(fp);
return FALSE;
}
}
printf("沒有你要查詢的書籍\n");
fclose(fp);
return FALSE;
}
findbook1()
{
FILE *fp;
char bookcreat[10];
int ture,i;
fp=fopen("book.txt","r");
printf("請輸入你要查找的作者名\n");
scanf("%s",bookcreat);
for(i=0;fread(&book[i],sizeof(struct book),1,fp)!=0;i++)
{
if(strcmp(bookcreat,book[i].bookcreat)==0)
{
if(book[i].turefalse==1)
{
printf("這本書的詳細資料是：%d %s %s 此書現在無人借閱\n按任意鍵返回\n",book[i].booknum,book[i].bookname,book[i].bookcreat);
}
else {printf("這本書已經有人借出\n");fclose(fp);return 0;}
fclose(fp);
return FALSE;
}
}
printf("沒有你要查詢的書籍\n");
fclose(fp);
return FALSE;
}
lendcount()
{
FILE *fp;
int i,n=0;
fp=fopen("record.txt","r");
for(i=0;fread(&student[i],sizeof(struct student),1,fp)!=0;i++)
{
printf("卡號：%d 借出的書籍：%s \n",student[i].carnum,student[i].lendbook);
n=n+1;
}
fclose(fp);
printf("目前共有%d本書借出\n",n);
printf("按任意鍵\n");
getch();
return n;
}
chabook()
{
char ch5;
do
{
printf("---------------歡迎進入圖書查詢系統！--------------\n");
printf(" 1：<按書名查找>\n");
printf(" 2：<按作者查找>\n");
printf(" 0：<返回>\n");
printf("請輸入0--2,其他輸入非法！\n");
scanf("%s",&ch5);
switch(ch5)
{
case '1':findbook();getch();break;
case '2':findbook1();getch();break;
case '0':break;
default:printf("無此操作\n");getch();break;
}
}while(ch5!='0');
return FALSE;
}
lendbook()
{
FILE *fp,*fp2;
int i,n;
int carnum;
printf("請你輸入你的卡號\n");
scanf("%d",&carnum);
fp=fopen("car.txt","r");
for(i=0;fread(&car[i],sizeof(struct car),1,fp)!=0;i++)
{
if(car[i].carnum==carnum)
{
n=i;
fclose(fp);
printf("請輸入你要借閱的書的名字\n");
scanf("%s",student[n].lendbook);
fp=fopen("book.txt","r");
for(i=0;fread(&book[i],sizeof(struct book),1,fp)!=0;i++)
{
if(strcmp(book[i].bookname,student[n].lendbook)==0)
{
if(book[i].turefalse==0) {printf("對不起，此書有人借出，請借其他書\n");fclose(fp);getch();return;}
else
fclose(fp);
fp=fopen("record.txt","a+");
student[n].carnum=carnum;
fwrite(&student[n],sizeof(struct student),1,fp);
fclose(fp);
fp=fopen("book.txt","r");
fp2=fopen("bookl.txt","w");
for(i=0;fread(&book[i],sizeof(struct book),1,fp)!=0;i++)
{
if(strcmp(book[i].bookname,student[n].lendbook)==0)
{
book[i].turefalse=0;
fwrite(&book[i],sizeof(struct book),1,fp2);
continue;
}
fwrite(&book[i],sizeof(struct book),1,fp2);
}
fclose(fp);
fclose(fp2);
fp=fopen("book.txt","w");
fp2=fopen("bookl.txt","r");
for(i=0;fread(&book[i],sizeof(struct book),1,fp2)!=0;i++)
{
fwrite(&book[i],sizeof(struct book),1,fp);
}
fclose(fp);
fclose(fp2);
fopen("bookl.txt","w");
fclose(fp2);
printf("借書完畢，按任意鍵返回\n");
getch();
return;
}
}
printf("不存在這樣的書，任意鍵返回\n");
fclose(fp);
getch();
return;
}
}
printf("你的卡號不存在，請申請新卡,按任意鍵返回\n");
fclose(fp);
getch();
}
carcount()
{
FILE *fp;
int i,n=0;
fp=fopen("car.txt","r");
for(i=0;fread(&car[i],sizeof(struct car),1,fp)!=0;i++)
{
printf("第%d張卡<卡號：%d 姓名：%s 班級：%d>\n",i+1,car[i].carnum,car[i].studentname,car[i].studentclass);
n=n+1;
}
fclose(fp);
printf("目前共有%d本書\n",n);
printf("按任意鍵\n");
getch();
}
delcar()
{
FILE *fp,*fp2;
int i;
int carnum;
char choice;
fp=fopen("car.txt","r");
fp2=fopen("bookl.txt","w");
printf("請輸入你要刪除的卡號\n");
printf("如果你輸入的卡號存在，系統自動刪除該信息！如果不存在，系統不做任何改動\n");
scanf("%d",&carnum);
for(i=0;fread(&car[i],sizeof(struct car),1,fp)!=0;i++)
{
if(car[i].carnum!=carnum)
{
fwrite(&car[i],sizeof(struct car),1,fp2);
}
}
fclose(fp);
fclose(fp2);
printf("是否真的要刪除該卡？刪除後該書籍的所有信息將無法恢復《Y/N》\n");
scanf("%s",&choice);
if(choice=='y'||choice=='Y')
{
fp=fopen("car.txt","w");
fp2=fopen("bookl.txt","r");
for(i=0;fread(&car[i],sizeof(struct car),1,fp2)!=0;i++)
{
fwrite(&car[i],sizeof(struct car),1,fp);
}
fclose(fp);
fclose(fp2);
fp2=fopen("bookl.txt","w");
fclose(fp2);
printf("按任意鍵返回\n");
getch();
return;
}
else
{
printf("按任意鍵返回\n");
getch();
return;
}
}
addcar()
{
FILE *fp;
int i=0;
fp=fopen("car.txt","a+");
printf("請你輸入卡號\n");
scanf("%d",&car[i].carnum);
printf("請你輸入學生姓名\n");
scanf("%s",car[i].studentname);
printf("請你輸入班級\n");
scanf("%d",&car[i].studentclass);
fwrite(&car[i],sizeof(struct car),1,fp);
fclose(fp);
printf("輸入完畢，任意鍵返回\n");
getch();
}
changemploy()
{
FILE *fp,*fp2;
char employname[10],choice;
int i;
fp=fopen("employ.txt","r");
fp2=fopen("bookl.txt","w");
printf("請你輸入要修改的職工的名字\n");
scanf("%s",employname);
for(i=0;fread(&employ[i],sizeof(struct employ),1,fp)!=0;i++)
{
if(strcmp(employ[i].employname,employname)==0)
{
printf("你所要修改的職工的資料如下，請選擇你要修改的內容\n");
printf("<職工號:%d職工名：%s 年齡：%d 性別：%s 學歷：%s 工資：%d>\n",employ[i].employnum,employ[i].employname,employ[i].employage,employ[i].employsex,employ[i].employleve,employ[i].employtage);
printf("2：修改職工名\n");
printf("3：修改職工年齡\n");
printf("4：修改職工工資\n");
printf("5：修改職工學歷\n");
printf("請輸入1-5:");
scanf("%s",&choice);
switch(choice)
{
case '1':
{
printf("請輸入新的職工號\n");
scanf("%d",&employ[i].employnum);
fwrite(&employ[i],sizeof(struct employ),1,fp2);
}break;
case '2':
{
printf("請輸入新的職工姓名\n");
scanf("%s",employ[i].employname);
fwrite(&employ[i],sizeof(struct employ),1,fp2);
}break;
case '3':
{
printf("請輸入新的年齡\n");
scanf("%d",&employ[i].employage);
fwrite(&employ[i],sizeof(struct employ),1,fp2);
}break;
case '4':
{
printf("請輸入新的職工工資\n");
scanf("%d",&employ[i].employtage);
fwrite(&employ[i],sizeof(struct employ),1,fp2);
}break;
case '5':
{
printf("請輸入新的職工學歷\n");
scanf("%s",employ[i].employleve);
fwrite(&employ[i],sizeof(struct employ),1,fp2);
}
default:printf("沒有這樣的操作");break;
}
continue;
}
fwrite(&employ[i],sizeof(struct employ),1,fp2);
}
fclose(fp);
fclose(fp2);
fp=fopen("employ.txt","w");
fp2=fopen("bookl.txt","r");
for(i=0;fread(&employ[i],sizeof(struct employ),1,fp2)!=0;i++)
{
fwrite(&employ[i],sizeof(struct employ),1,fp);
}
fclose(fp);
fclose(fp2);
fp2=fopen("bookl.txt","w");
fclose(fp2);
printf("按任意鍵返回\n");
getchar();
return;
}
delemploy()
{
FILE *fp,*fp2;
int i;
char employname[10],choice;
fp=fopen("employ.txt","r");
fp2=fopen("bookl.txt","w");
printf("請輸入你要刪除的職工名\n");
printf("如果你輸入的職工存在，系統自動刪除該信息！如果不存在，系統不做任何改動\n");
scanf("%s",employname);
for(i=0;fread(&employ[i],sizeof(struct employ),1,fp)!=0;i++)
{
if(strcmp(employname,employ[i].employname)!=0)
{
fwrite(&employ[i],sizeof(struct employ),1,fp2);
}
}
fclose(fp);
fclose(fp2);
printf("是否真的要刪除該職工信息？刪除後的所有信息將無法恢復《Y/N》\n");
scanf("%s",&choice);
if(choice=='y'||choice=='Y')
{
fp=fopen("employ.txt","w");
fp2=fopen("bookl.txt","r");
for(i=0;fread(&employ[i],sizeof(struct employ),1,fp2)!=0;i++)
{
fwrite(&employ[i],sizeof(struct employ),1,fp);
}
fclose(fp);
fclose(fp2);
fp2=fopen("bookl.txt","w");
fclose(fp2);
printf("按任意鍵返回\n");
getch();
return TRUE;
}
else
{
printf("按任意鍵返回\n");
getch();
return FALSE;
}
}
employcount()
{
FILE *fp;
int i,n=0;
fp=fopen("employ.txt","r");
for(i=0;fread(&employ[i],sizeof(struct employ),1,fp)!=0;i++)
{
printf("第%d職工的信息如下：\n<職工號：%d 職工名：%s 年齡：%d 性別：%s 學歷：%s 工資：%d>\n",n+1,employ[i].employnum,employ[i].employname,employ[i].employage,employ[i].employsex,employ[i].employleve,employ[i].employtage);
n++;
}
fclose(fp);
printf("目前共有%d個職工\n",n);
printf("按任意鍵返回\n");
}
addemploy()
{
FILE *fp;
char choice='y';
int i=1;
fp=fopen("employ.txt","a+");
while(choice=='y'||choice=='Y')
{
printf("請你輸入職工號碼\n");
scanf("%d",&employ[i].employnum);
printf("請你輸入職工名\n");
scanf("%s",employ[i].employname);
printf("請輸入職工年齡\n");
scanf("%d",&employ[i].employage);
printf("請你輸入性別\n");
scanf("%s",employ[i].employsex);
printf("請你輸入職工的學歷水平\n");
scanf("%s",employ[i].employleve);
printf("請輸入職工的工資\n");
scanf("%d",&employ[i].employtage);
fwrite(&employ[i],sizeof(struct employ),1,fp);
printf("是否要輸入下個職工信息？\n");
scanf("%s",&choice);
}
printf("按任意鍵返回\n");
fclose(fp);
}
addbook()
{
FILE *fp;
int i=0;
char choice='y';
fp=fopen("book.txt","a+");
while(choice=='y'||choice=='Y')
{
printf("請你輸入第%d本書的序號\n",i+1);
scanf("%d",&book[i].booknum);
printf("請你輸入書名\n");
scanf("%s",book[i].bookname);
printf("請你輸入書的作者\n");
scanf("%s",book[i].bookcreat);
printf("請設為1或0，1代表書還沒人借，0表示書已經借出，設其他值，程序運行時無法得出正常結果\n");
printf("請你設定書的狀態\n");
scanf("%d",&book[i].turefalse);
fwrite(&book[i],sizeof(struct book),1,fp);
printf("是否要輸入下本書\n");
scanf("%s",&choice);
}
fclose(fp);
}
bookcount()
{
FILE *fp;
int i,n=0;
fp=fopen("book.txt","r");
for(i=0;fread(&book[i],sizeof(struct book),1,fp)!=0;i++)
{
if(book[i].booknum!=0&&strlen(book[i].bookname)!=0&&strlen(book[i].bookcreat)!=0)
{
printf("第%d本書<序號：%d 書名：%s 作者：%s 狀態：%d>\n",i+1,book[i].booknum,book[i].bookname,book[i].bookcreat,book[i].turefalse);
n=n+1;
}
}
fclose(fp);
printf("目前共有%d本書\n",n);
printf("按任意鍵\n");
}
delbook()
{
FILE *fp,*fp2;
int i;
char bookname[10],choice;
fp=fopen("book.txt","r");
fp2=fopen("bookl.txt","w");
printf("請輸入你要刪除的書名\n");
printf("如果你輸入的書名存在，系統自動刪除該信息！如果不存在，系統不做任何改動\n");
scanf("%s",bookname);
for(i=0;fread(&book[i],sizeof(struct book),1,fp)!=0;i++)
{
if(strcmp(bookname,book[i].bookname)!=0)
{
fwrite(&book[i],sizeof(struct book),1,fp2);
}
}
fclose(fp);
fclose(fp2);
printf("是否真的要刪除該書籍？刪除後該書籍的所有信息將無法恢復《Y/N》\n");
scanf("%s",&choice);
if(choice=='y'||choice=='Y')
{
fp=fopen("book.txt","w");
fp2=fopen("bookl.txt","r");
for(i=0;fread(&book[i],sizeof(struct book),1,fp2)!=0;i++)
{
fwrite(&book[i],sizeof(struct book),1,fp);
}
fclose(fp);
fclose(fp2);
fp2=fopen("bookl.txt","w");
fclose(fp2);
printf("按任意鍵返回\n");
getch();
return;
}
else
{
printf("按任意鍵返回\n");
getch();
return;
}
}
changebook()
{
FILE *fp,*fp2;
char bookname[10],choice;
int i;
fp=fopen("book.txt","r");
fp2=fopen("bookl.txt","w");
printf("請你輸入要修改的書籍的書字\n");
scanf("%s",bookname);
for(i=0;fread(&book[i],sizeof(struct book),1,fp)!=0;i++)
{
if(strcmp(book[i].bookname,bookname)==0)
{
printf("你所要修改的書的資料如下，請選擇你要修改的內容\n");
printf("序號：〈%d〉 書名：〈%s〉 作者：〈%s〉 \n",book[i].booknum,book[i].bookname,book[i].bookcreat);
printf("1：修改書的序號\n");
printf("2：修改書名\n");
printf("3：修改作者\n");
printf("請輸入1-3:");
scanf("%s",&choice);
switch(choice)
{
case '1':
{
printf("請輸入新的序號\n");
scanf("%d",&book[i].booknum);
fwrite(&book[i],sizeof(struct book),1,fp2);
}break;
case '2':
{
printf("請輸入新的書名\n");
scanf("%s",book[i].bookname);
fwrite(&book[i],sizeof(struct book),1,fp2);
}break;
case '3':
{
printf("請輸入新的作者\n");
scanf("%s",book[i].bookcreat);
fwrite(&book[i],sizeof(struct book),1,fp2);
}break;
defaut:printf("沒有這樣的操作");break;
}
continue;
}
fwrite(&book[i],sizeof(struct book),1,fp2);
}
fclose(fp);
fclose(fp2);
fp=fopen("book.txt","w");
fp2=fopen("bookl.txt","r");
for(i=0;fread(&book[i],sizeof(struct book),1,fp2)!=0;i++)
{
fwrite(&book[i],sizeof(struct book),1,fp);
}
fclose(fp2);
fp2=fopen("bookl.txt","w");
fclose(fp2);
printf("按任意鍵返回\n");
getchar();
return;
}
main()
{
char ch1,ch2,ch3,ch4,ch5;
do
{
printf("\t\t請你選擇操作類型:\n");
printf(" 1：<查閱圖書>\n");
printf(" 2：<借閱圖書>\n");
printf(" 3：<管理系統>\n");
printf(" 4：<還書>\n");
printf(" 0：<退出>\n");
printf("請輸入0--4\n");
scanf("%s",&ch1);
switch(ch1)
{
case '1':chabook();break;
case '2':lendbook();;break;
case '3':{
do
{
printf("---------------歡迎進入管理系統！--------------\n");
printf(" 1：<增加圖書>\n");
printf(" 2：<刪除圖書>\n");
printf(" 3：<修改圖書資料>\n");
printf(" 4：<書籍統計>\n");
printf(" 5：<職工管理系統>\n");
printf(" 6：<學生管理系統>\n");
printf(" 0：<返回>\n");
printf("請輸入0--6,其他輸入非法！\n");
scanf("%s",&ch2);
switch(ch2)
{
case '1':addbook();
break;
case '2':delbook();break;
case '3':changebook();break;
case '4':bookcount();getch();break;
case '5':{do
{
printf("---------------歡迎進入職工管理系統！--------------\n");
printf(" 1：<增加員工>\n");
printf(" 2：<刪除員工>\n");
printf(" 3：<修改員工資料>\n");
printf(" 4：<員工統計>\n");
printf(" 0：<返回>\n");
printf("請輸入0--4,其他輸入非法！\n");
scanf("%s",&ch3);
switch(ch3)
{
case '1':addemploy();getch();break;
case '2':delemploy();break;
case '3':changemploy();break;
case '4':employcount();getch();break;
case '0':break;
default:printf("無此操作\n");getch();break;
}
}while(ch3!='0');}break;
case '6':{
do
{
printf("---------------歡迎進入學生管理系統！--------------\n");
printf(" 1：<申請新卡>\n");
printf(" 2：<刪除卡號>\n");
printf(" 3：<借書統計>\n");
printf(" 4：<卡號統計>\n");
printf(" 0：<返回>\n");
printf("請輸入0--4,其他輸入非法！\n");
scanf("%s",&ch4);
switch(ch4)
{
case '1':addcar();break;
case '2':delcar();break;
case '3':lendcount();break;
case '4':carcount();break;
case '0':break;
default:printf("無此操作\n");getch();break;
}
}while(ch4!='0');}break;
case '0':break;
default:printf("無此操作\n");getch();break;
}
}while(ch2!='0');}break;
case '4':huanbook();break;
case '0':break;
default:printf("無此操作\n");getch();break;
}
}while(ch1!='0');
}
Ⅳ 如何看c語言標准庫函數的源代碼
很遺憾,標准庫中的函數結合了系統,硬體等的綜合能力,是比較近機器的功能實現,所以大部分是用匯編完成的,而且已經導入到了lib和dll里了,就是說,他們已經被編譯好了,似乎沒有代碼的存在了.
能看到的也只有dll中有多少函數被共享.
第三方可能都是dll,因為上面也說了,dll是編譯好的,只能看到成品,就可以隱藏代碼,保護自己的知識產權,同時也是病毒的歸宿...... 當然,除了DLL的確還存在一種東西,插件程序~~~
Ⅳ 如何查看C語言，內庫的源代碼
1、首先標准只是規定了這些函數的介面和具體的運行效率的要求，這些函數具體是怎麼寫得要看各個編譯器的實現和平台。
2、例如使用的編譯器是visual studio，微軟提供了一部分C運行時(CRT)的源碼，裡面會有memcpy，strcpy之類的函數的實現，在visual studio 2005下的路徑是C:\Program Files\Microsoft Visual Studio 8\VC\crt\src。