嗯，lynx 是一个交互式程序，所以我认为在 system() 调用中使用它时会遇到麻烦。但不是curl：
/* pru_curl-1.c */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
char *cmd = "curl https://www.google.com/";
system(cmd); /* you will get the output of curl on stdout */
exit(EXIT_SUCCESS);
}
这是 curl 在 shell 调用中使用 > 运算符重定向其输出：
/* pru_curl-2.c */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
char *cmd = "curl https://www.google.com/ >output_file-2";
/* you will get the output of curl on output_file-2 */
system(cmd);
exit(EXIT_SUCCESS);
}
另一方面，Curl 允许您指定 -o output_file.txt，一旦程序完成，您就可以读取文件。
/* pru_curl-3.c */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
char *cmd = "curl https://www.google.com/ -o output_file-3";
/* you will get the output of curl on output_file-3 */
system(cmd);
exit(EXIT_SUCCESS);
}
您还有第三种选择，即使用popen(3)，它允许您将程序作为子命令启动，并从您从popen(3) 获得的FILE * 描述符中读取该程序的输出。你可以这样使用它（逐个字符处理）：
/* pru_curl-4.c */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
char *cmd = "curl https://www.google.com/";
FILE *f = popen(cmd, "r");
if (!f) {
fprintf(stderr, "%s: %s\n",
cmd, strerror(errno));
exit(EXIT_FAILURE);
}
int c;
while((c = fgetc(f)) != EOF) {
printf("[%d]", c); /* you will get the downloaded file as
* sequences of numbers (the character
* values) embedded in square brackets on
* stdout */
}
pclose(f);
exit(EXIT_SUCCESS);
}
或（逐行处理）：
/* pru_curl-5.c */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
char *cmd = "curl https://www.google.com/";
FILE *f = popen(cmd, "r");
if (!f) {
fprintf(stderr, "%s: %s\n",
cmd, strerror(errno));
exit(EXIT_FAILURE);
}
char line[256];
while (fgets(line, sizeof line, f)) {
/* you'll get your output in chunks of one line, or 256 bytes
* ---if longer---, encapsulated by a pair of square brackets
* drawn in a different color (gren, by the escape sequences
* used) */
fprintf(stderr,
"\033[1;33m[\033[m%s\033[32m]\033[m",
line);
}
pclose(f);
exit(EXIT_SUCCESS);
}
或（按块）：
/* pru_curl-6.c */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 8 /* blocks in buffer */
#define CPB 11 /* chars per block */
int main()
{
char *cmd = "curl https://www.google.com/";
FILE *f = popen(cmd, "r");
if (!f) {
fprintf(stderr, "%s: %s\n",
cmd, strerror(errno));
exit(EXIT_FAILURE);
}
char block[N][CPB];
int n;
char *sep = "";
do {
/* print a blanck line between groups */
printf("%s", sep);
sep = "\n";
/* we read as many CPB byte blocks as possible to fill the
* N registers in buffer.
* Then we start again until we don't fill completely the
* buffer. */
n = fread(block, sizeof block[0], N, f);
int i;
for (i = 0; i < n; i++) {
printf("[%.*s]\n", (int)sizeof block[i], block[i]);
}
printf("finished one loop of %d blocks of %d chars, each.\n",
N, (int) sizeof block[0]);
} while (n == N);
/* n < N, so we are finished, check that probably the last register is
* not printed because it was not complete. */
pclose(f);
exit(EXIT_SUCCESS);
}
（所有这些示例都是完整的，并且在发布前已经过测试）
编辑
我已经完成了六个程序的代码，现在它们都是可执行的，只需构建：
$ cc pru_curl-<i>.c -o pru_curl-<i> # <i> is the program number
$ _
在每种情况下，您都可以通过运行来执行程序：
$ pru_curl-<i>
.... <-- a lot of output (or to a file) about the contents of the root page of google.
$ _