program givin error when gchar is initialized

问题

in my main.h (which is included in all other src file), I have:

char* buffer;

This compiles and workes fine.

For some other reason, I tried to initialize buffer, both as

char* buffer="";

and

char* buffer="\0";

Now, building it is giving error:

src/search.o:(.data+0x0): multiple definition of `buffer'
src/bib.o:(.data+0x0): first defined here
src/mkbib.o:(.data+0x0): multiple definition of `buffer'
src/bib.o:(.data+0x0): first defined here
src/update_file.o:(.data+0x0): multiple definition of `buffer'
src/bib.o:(.data+0x0): first defined here
src/view.o:(.data+0x0): multiple definition of `buffer'
src/bib.o:(.data+0x0): first defined here
src/file_util.o:(.data+0x0): multiple definition of `buffer'
src/bib.o:(.data+0x0): first defined here
collect2: error: ld returned 1 exit status
make[2]: *** [mkbib] Error 1

The problem is bib.o is generated from a bison file (bison -d). buffer is NOT defined there:

$ grep buffer src/bib.y
$

buffer is also never defined ANYWHERE else, but used:

$grep buffer src/*.c
src/file_util.c:  44   :  g_file_set_contents(filename, buffer, -1, &Err);
src/file_util.c:  51   ://  g_free(buffer);
src/file_util.c:  75   :    g_file_set_contents(filename, buffer, -1, &Err);
src/file_util.c:  76   ://    g_free(buffer);
src/file_util.c: 140   :    g_file_get_contents(filename, &buffer, &length , &error);
src/file_util.c: 152   ://    g_free(buffer);
src/search.c:  99      :  GtkTextBuffer *gs_buf=gtk_text_view_get_buffer(GTK_TEXT_VIEW(gs_txt));
src/search.c: 100      :  gtk_text_buffer_get_start_iter (gs_buf, &start);
src/search.c: 101      :  gtk_text_buffer_get_end_iter (gs_buf, &end);
src/search.c: 102      :  gchar *gs_text = gtk_text_buffer_get_text (gs_buf, &start, &end, FALSE);
src/search.c: 103      :  strcat(buffer, gs_text);
src/update_file.c: 106 :    GString *str=g_string_new(buffer);
src/update_file.c: 132 :    buffer=str->str;
src/view.c:  38:  yyin=fmemopen(buffer,strlen(buffer),"r");
src/view.c: 178:  //  g_free(buffer);
src/view.c: 259:  buffer=str->str;
$

NB: I can also recall having same type of error adding another character variable in main.h few days back, left the problem that time.

回答1:

Use:

extern char *buffer;  // declares buffer, but doesn't define it

in your main.h

and be sure your definition of buffer appears only once in one .c file as:

char *buffer = "";  // not equivalent to = "\0"

来源：https://stackoverflow.com/questions/17054979/program-givin-error-when-gchar-is-initialized

标签

initialization

bison