C:stdin和std *错误 [英] C: stdin and std* errs
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问题描述
我要先操纵Stdin
,然后再操纵Std*
.但是我遇到了以下错误,
I want to manipulate Stdin
and then Std*
. But I am getting the following errors,
$ gcc testFd.c
testFd.c:9: error: initializer element is not constant
testFd.c:9: warning: data definition has no type or storage class
testFd.c:10: error: redefinition of `fd'
testFd.c:9: error: `fd' previously defined here
testFd.c:10: error: `mode' undeclared here (not in a function)
testFd.c:10: error: initializer element is not constant
testFd.c:10: warning: data definition has no type or storage class
testFd.c:12: error: syntax error before string constant
程序如下所示.
#include <stdio.h>
#include <sys/ioctl.h>
int STDIN_FILENO = 1;
// I want to access typed
// Shell commands, dunno about the value:
unsigned long F_DUPFD;
fd = fcntl(STDIN_FILENO, F_DUPFD, 0);
fd = open("/dev/fd/0", mode);
printf("STDIN = %s", fd);
更新的错误:仅试图获取有关文件描述符的示例程序以在C中工作,而在err报告中却迷失了
#include <stdio.h>
#include <sys/ioctl.h>
int main (void) {
int STDIN_FILENO;
// I want to access typed
// Shell commands, dunno about the value:
unsigned long F_DUPFD;
int fd;
const char mode = 'r';
fd = fcntl(STDIN_FILENO, F_DUPFD, 0);
/* also, did you mean `fopen'? */
fd = fopen("/dev/fd/0", mode);
printf("STDIN = %s", fd);
return 0;
}
程序执行如下所示.
$ gcc testFd.c
testFd.c: In function `main':
testFd.c:14: warning: passing arg 2 of `fopen' makes pointer from integer without a cast
testFd.c:14: warning: assignment makes integer from pointer without a cast
推荐答案
尝试使用main
方法:
#include <stdio.h>
#include <sys/ioctl.h>
int main (void) {
int STDIN_FILENO = 1;
// I want to access typed
// Shell commands, dunno about the value:
unsigned long F_DUPFD;
/* also, declare the type of your variable "fd" */
int fd;
fd = fcntl(STDIN_FILENO, F_DUPFD, 0);
/* also, did you mean `fopen'? */
fd = open("/dev/fd/0", mode);
printf("STDIN = %s", fd);
return 0;
}
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