exit 的一点问题
#include<stdio.h>void main()
{
FILE *fp;
char ch;
if((fp=fopen("file.txt","w"))==NULL)
{
printf("can't open file.\n");
exit(0);
}
while((ch=getchar())!='\n')
fputc(ch,fp);
fclose(fp);
}
像以上程序,它为什么总会报一个 'exit' undefinedassumingexternreturningint 的警告呢? LZ要指明用了什么什么环境和什么编译器.我用VC8的编译器编译没报exit的错.只有fopen相关的:
z.c(6) : warning C4996: 'fopen' was declared deprecated
D:\\Program Files\\Microsoft Visual Studio 8\\VC\\include\\stdio.h(234) : see
declaration of 'fopen'
Message: 'This function or variable may be unsafe. Consider using fopen_
s instead. To disable deprecation, use _CRT_SECURE_NO_DEPRECATE. See online help
for details.' 是VC++6.0 加一个#include<stdlib.h>
就不会警告了,至于什么原因,应该能猜出来了吧?
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