linux openpty函数,popen函数及输出错误信息

ゞ浴缸里的玫瑰 2023-01-21 02:22 2阅读 0赞

\#include // popen, printf, snprintf

\#include // WIFEXITED() WEXITSTATUS()

\#include // extern int errno;

\#include

\#define MAX\_SIZE (1024)

bool exec\_cmd(const char\* command, std::string& errmsg)

assert(command);

char buffer\[MAX\_SIZE\] = \{'\\0'\};

std::string final\_msg;

// the exit status of the command.

int rc = 0;

// I/O redirection.

char cmd\[MAX\_SIZE\] = \{'\\0'\};

snprintf(cmd, sizeof(cmd), "%s 2>&1", command);

FILE \*fp = popen(cmd, "r");

if(NULL == fp)

\{ // if fork(2) or pipe(2) calls fail, or cannot callocate memory.

// it does not set errno if memory allocation fails.

// if the underlying fork(2) or pipe(2) fails, errno is set

// appropriately.

// if the type arguments is invalid, and this condition is detected,

// errno is set to EINVAL.

snprintf(buffer, sizeof(buffer),

"popen failed. %s, with errno %d.\\n", strerror(errno), errno);

final\_msg = buffer;

errmsg = final\_msg.c\_str();

return false;

char result\[MAX\_SIZE\] = \{'\\0'\};

std::string child\_result;

while(fgets(result, sizeof(result), fp) != NULL)

// remove the '\\n' to make output more beautiful

if('\\n' == result\[strlen(result)-1\])

result\[strlen(result)-1\] = '\\0';

snprintf(buffer, sizeof(buffer),

"\[%s\]: %s \\r\\n", command, result);

child\_result += buffer;

// waits for the associated process to terminate and returns

// the exit status of the command as returned by wait4(2).

rc = pclose(fp);

if(-1 == rc)

\{ // return -1 if wait4(2) returns an error, or some other error is detected.

// if pclose cannot obtain the child status, errno is set to ECHILD.

final\_msg += child\_result;

if(ECHILD==errno) \{

final\_msg += "pclose cannot obtain the child status.\\n";

else \{

snprintf(buffer, sizeof(buffer),

"Close file failed. %s, with errno %d.\\n", strerror(errno), errno);

final\_msg += buffer;

errmsg = final\_msg.c\_str();

return false;

// TODO: warning 'file descriptor leaked

\#if 0

if(WIFEXITED(rc)!=0) \{

printf("maybe cause file descriptor leaked.\\n");

\#endif

// child process exit status.

int status\_child = WEXITSTATUS(rc);

// the success message is here.

final\_msg += child\_result;

snprintf(buffer, sizeof(buffer),

"\[%s\]: command exit status \[%d\] and child process exit status \[%d\].\\r\\n",

command, rc, status\_child);

final\_msg += buffer;

errmsg = final\_msg.c\_str();

if(status\_child==0) \{

// child process exits SUCCESS.

return true;

else \{

// child process exits FAILED.

return false;

bool getCmdPath(const char\* cmd, String& path)

if (cmd == NULL || strlen(cmd) == 0)

return false;

string command = "which ";

command += cmd;

FILE\* pf = popen(command.c\_str(), "r");

if (pf) \{

char buf\[100\];

memset(buf, '\\0', sizeof(buf));

fgets(buf, sizeof(buf), pf);

pclose(pf);

//return the path

path = buf;

return true;

\} else \{

return false;

调用popen函数，执行shell 命令，并输出错误信息。

linux openpty函数,popen函数及输出错误信息

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