StackOverflow2013

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plurals

PO
primarykey
Id
20060317
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
13
CommunityOwnedDate
CreationDate
2013-11-18T23:41:06.763
FavoriteCount
0
LastActivityDate
2013-11-19T00:04:12.620
LastEditDate
2017-05-23T10:25:38.393
LastEditorUserId
-1
OwnerUserId
1422070
ParentId
20060246
PostTypeId
2
Score
0
ViewCount
0
LastEditorDisplayName
text
Body
You are reading into a buffer you never allocated memory for. What you're trying now is to read from some junk value in memory, who knows, which almost always leads to a segmentation fault. Use: <pre><code>char *buffer = malloc(512 * sizeof(char)); // this allocates 512 times the size of a single char of memory </code></pre> If you don't specify the number inside malloc to be of a specific size (e.g. malloc(512) the number is in bytes, though I think it's better to always include it. This specific error is called <a href="https://stackoverflow.com/questions/4007268/what-exactly-is-meant-by-de-referencing-a-null-pointer">dereferencing a null pointer</a> EDIT: I've managed to run this code: <pre><code>#include <stdio.h> #include <stdlib.h> #include <string.h> int main (int argc, char **argv) { FILE *fp ,*fptest; long lSize; char *buffer; //Open file fptest = fopen("input.txt", "rb"); if (fptest == NULL) { printf("Error occurred when opening file"); return 1; } buffer = malloc(sizeof(char) * 512); //Read file into buffer fread(buffer,1,512,fptest); //Parse the boot sector char tmpA, tmpB; tmpA = buffer[10]; //First byte tmpB = buffer[11]; //Second byte //Combine the two bytes into one char combinedBytes[3]; strcpy (combinedBytes, &tmpA); strcat (combinedBytes, &tmpB); //Hex to decimal converter long int li1; li1 = strtol (combinedBytes,NULL,16); printf ("The sector size is: %ld.\n", li1); return 0; } </code></pre> You also used a function <code>open()</code> which must be <code>fopen()</code>, and you need to pass the address of tmpA and tmpB to strcpy and strcat. This is why I don't understand why your compiler doesn't give any errors or warnings..
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Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POSegmentation fault in reading a .dat file
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 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. USCommunity
UserOwnerUserId
1. USedwardmp
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1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. POSegmentation fault in reading a .dat file
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PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. VO
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