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POSegmentation fault when returning a struct
primarykey
Id
3378972
data
AcceptedAnswerId
3379005
AnswerCount
2
ClosedDate
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4
CommunityOwnedDate
CreationDate
2010-07-31T16:45:29.173
FavoriteCount
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2010-08-01T15:26:19.003
LastEditDate
2017-05-23T12:07:08.033
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271789
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0
PostTypeId
1
Score
2
ViewCount
982
LastEditorDisplayName
text
Body
<p>I am trying to do a pretty simple thing - it is reading a file and then turning it into a char** splitting it into lines. However when I return a struct containing the char** and size i get Segmentation fault. I read here: <a href="https://stackoverflow.com/questions/3047163/c-segmentation-fault-before-during-return-statement">C segmentation fault before/during return statement</a> that it's probably "mangled stack". I still however don't know what I did to mangle it. This is my code:</p> <pre><code>#include <stdio.h> #include <string.h> #include <stdlib.h> #include <ctype.h> #include "comp_words.h" #define BLOCK 4096 struct sized_str { char* str; long size; }; struct sized_arr { char** content; int size; }; struct sized_str readfile(char* name) { FILE *f; long filesize; char *buf; struct sized_str res; int r, p = 0; f = fopen(name, "r"); fseek(f, 0, SEEK_END); filesize = ftell(f); rewind(f); buf = calloc(filesize + 1, sizeof(char)); while ((r = fread(buf + p, sizeof(char), BLOCK, f))) { p += r; } res.str = buf; res.size = filesize + 1; return res; } struct sized_arr read_dict() { struct sized_str file_content; struct sized_arr result; char *buf, *buf_cpy, *buf_cpy_point, *line, **res; int i = 0, j, line_count = 0; file_content = readfile("/var/tmp/twl06.txt"); buf = file_content.str; buf_cpy = (char*)malloc(file_content.size * sizeof(char)); strcpy(buf_cpy, buf); buf_cpy_point = buf_cpy; while (strtok(buf_cpy_point, "\n\r")) { line_count++; buf_cpy_point = NULL; } res = (char**)malloc(sizeof(char*) * line_count); while ((line = strtok(buf, "\n\r"))) { res[i] = (char*)malloc(sizeof(char) * strlen(line)); j = 0; while ((res[i][j] = tolower(line[j]))) { j++; } buf = NULL; } free(buf_cpy); result.size = line_count; result.content = res; return result; } // ... int main (int argc, char** argv) { struct sized_str input; struct sized_arr dict; dict = read_dict(); // ... return 0; </code></pre> <p>The code segfaults while returning from read_dict function.</p>
Tags
<c><struct><malloc><segmentation-fault>
Title
Segmentation fault when returning a struct
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