/* * This page documents the getcwd(2) system call, which * is not defined in any user-space header files; you should * use getcwd(3) defined in <unistd.h> instead in applications. */
long getcwd(char *buf, unsigned long size);
描述The getcwd() function copies an absolute pathname of the current working directory to the array pointed to by buf, which is of length size.
If the current absolute path name would require a buffer longer than size elements, -1is returned, and errno is set to ERANGE; an application should check for this error, and allocate a larger buffer if necessary.
If buf is NULL, the behaviour of getcwd() is undefined.
返回值-1 on failure (for example, if the current directory is not readable), with errno set accordingly, and the number of characters stored in buf on success. The contents of the array pointed to by buf is undefined on error.
Note that this return value differs from the getcwd(3) library function, which returnsNULL on failure and the address of buf on success.
|if user memory cannot be mapped|
|if directory does not exist (i.e. it has been deleted)|
|if not enough space available for storing the path|
if memory access violation occurs while copying
遵循于The getcwd system call is Linux specific, use the getcwd C library function for portability.