编译时出错？

Question

I am getting these errors when I am compiling my code. I have all the headers under user/include

g++ -Ip_appmanager/inc -Icore/inc p_appmanager/src/appmanager_process.cpp -o p_appmanager/obj/appmanager -lpthread -lparser
p_appmanager/src/appmanager_process.cpp: In function ‘int main(int, char**)’:
p_appmanager/src/appmanager_process.cpp:33:21: error: ‘getpid’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:101:19: error: ‘fork’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:105:70: error: ‘execl’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:109:19: error: ‘getppid’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:124:19: error: ‘fork’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:128:61: error: ‘execl’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:132:19: error: ‘getppid’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:147:19: error: ‘fork’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:151:73: error: ‘execl’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:155:19: error: ‘getppid’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:170:19: error: ‘fork’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:175:70: error: ‘execl’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:179:19: error: ‘getppid’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp: In function ‘void* pingThread(void*)’:
p_appmanager/src/appmanager_process.cpp:302:11: error: ‘sleep’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp: In function ‘void* fifoThread(void*)’:
p_appmanager/src/appmanager_process.cpp:815:22: error: ‘fork’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:818:72: error: ‘execl’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:842:64: error: ‘execl’ was not declared in this scope
p_appmanager/src/appmanager_process.cpp:865:72: error: ‘execl’ was not declared in this scope
make: *** [all] Error 1

my kernel version is "Linux amit-bhaira 3.8.0-26-generic #38-Ubuntu SMP Mon Jun 17 21:46:08 UTC 2013 i686 i686 i686 GNU/Linux" . Same code is running on another linux machine.

please help me to fix this problem.

Thanks.

Answer 1

Add #include <unistd.h>

It works on other platforms because they are compiling with an old version of gcc (<4.7) which accidentally included unistd.h in some system headers.

Answer 2

From the fork(2) man page:

SYNOPSIS
       #include <unistd.h>

From the exec(3) man page:

SYNOPSIS
       #include <unistd.h>

From the getpid(2) man page:

SYNOPSIS
       #include <sys/types.h>
       #include <unistd.h>

From the sleep(3) man page:

SYNOPSIS
       #include <unistd.h>

Answer 3

您已忘记程序中的#include <unistd.h> 。