如何使用 apr_file_open() 创建文件

Question

我对 Apache Portable Runtime 库（版本 1.4）进行以下调用：

result = apr_file_open(
    &file, // new file handle
    pathname, // file name          
    APR_FOPEN_CREATE | // create file if not there 
    APR_FOPEN_EXCL | // error if file was there already
    APR_FOPEN_APPEND | // move to end of file on open
    APR_FOPEN_BINARY | // binary mode (ignored on UNIX)
    APR_FOPEN_XTHREAD | // allow multiple threads to use file
    0, // flags
    APR_OS_DEFAULT |
    0, // permissions
    pool // memory pool to use
);

if ( APR_SUCCESS != result ) {
    fprintf(
        stderr,
        "could not create file \"%s\": %s",
        pathname,
        apr_errorstr( result )
    );
}

并pathname包含字符串/tmp/tempfile20110614091201.

我不断收到错误“权限被拒绝”（结果代码APR_EACCES），但我有读/写权限/tmp- 可能是什么原因导致的？

Answer 1

我需要APR_FOPEN_WRITE旗帜。我错误地认为APR_FOPEN_APPEND旗帜就足够了。

所以，有效的调用是：

    result = apr_file_open(
        &file, // new file handle
        pathname, // file name          
        APR_FOPEN_CREATE | // create file if not there 
        APR_FOPEN_EXCL | // error if file was there already
        APR_FOPEN_WRITE | // open for writing
        APR_FOPEN_APPEND | // move to end of file on open
        APR_FOPEN_BINARY | // binary mode (ignored on UNIX)
        APR_FOPEN_XTHREAD | // allow multiple threads to use file
        0, // flags
        APR_OS_DEFAULT |
        0, // permissions
        pool // memory pool to use
    );