RE: problem appending to a file

Alex.Krumm-Heller Wed, 04 Jan 2006 17:57:48 -0800

Whoops, I forgot to mention that this is occurring under windows, whereas it works fine under linux.

Alex

-----Original Message-----
From: Krumm-Heller, Alex (ICT Centre, Marsfield)
Sent: Thursday, 5 January 2006 12:38 PM
To: [email protected]
Subject: problem appending to a file

Hi,

I am trying to do some file I/O. The scenario I am aiming for is to create a file if it doesn’t exist, append to it if it exists as well as allowing for writes to the file from multiple threads. Yet when I use this combination of options in apr_file_open it always overwrites the file rather than appending to it. If I remove the multiple thread option from the open call, it appends correctly. Is this a bug or am I doing something wrong? Test case follows.

#include <string>

#include "apr_file_io.h"

int main(int argc, char* argv[])

{

if (apr_initialize() != APR_SUCCESS)

{

return -1;

}

apr_pool_t *context;

if (apr_pool_create(&context, NULL) != APR_SUCCESS)

{

fprintf(stderr, "Couldn't allocate context.");

exit(-1);

}

apr_file_t *logfile;

apr_status_t openstatus = apr_file_open(&logfile, "test.txt", APR_APPEND | APR_CREATE | APR_WRITE | APR_XTHREAD, APR_OS_DEFAULT, context);

if (openstatus != APR_SUCCESS)

{

return -1;

}

std::string output("String 1");

apr_size_t written;

apr_status_t writestatus = apr_file_write_full(logfile, output.c_str(), output.length(), &written);

if (writestatus != APR_SUCCESS || written != output.length())

{

}

apr_file_flush(logfile);

if (apr_file_close(logfile) != APR_SUCCESS)

{

return -1;

}

logfile = NULL;

openstatus = apr_file_open(&logfile, "test.txt", APR_APPEND | APR_CREATE | APR_WRITE | APR_XTHREAD, APR_OS_DEFAULT, context);

if (openstatus != APR_SUCCESS)

{

return -1;

}

output.assign("String 2");

written;

writestatus = apr_file_write_full(logfile, output.c_str(), output.length(), &written);

if (writestatus != APR_SUCCESS || written != output.length())

{

}

apr_file_flush(logfile);

if (apr_file_close(logfile) != APR_SUCCESS)

{

return -1;

}

logfile = NULL;

apr_pool_destroy(context);

apr_terminate();

return 0;

}

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RE: problem appending to a file

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