c

Separating functions to a separate header that rely on another function not inside the header?

I have several C scripts that will all have the same format(functions), but occasionally the actual code within a few functions. I am trying to separate a function into an external header file, but the issue is this: int FunctionImExtracting() { //some code FunctionThatCannotBeExtractedButTheFunctionSignatureWillAlwaysRemainThe...

why is strtof is always evaluating to HUGE_VAL?

What could be the issue here? It doesn't matter what number I choose for str, it is always 26815615859885194199148049996411692254958731641184786755447122887443528060147093953603748596333806855380063716372972101707507765623893139892867298012168192.00 char *str = "2.6"; printf("%f\n", strtof(str, (char**)NULL)); //prints 26815615859885194...

Why freed struct in C still has data?

When I run this code: #include <stdio.h> typedef struct _Food { char name [128]; } Food; int main (int argc, char **argv) { Food *food; food = (Food*) malloc (sizeof (Food)); snprintf (food->name, 128, "%s", "Corn"); free (food); printf ("%d\n", sizeof *food); printf ("%s\n", food->name); } I still get 128 Corn...

extracting pdf text in objective c

up to this point, i had not found a solution that would work well to extract text from a pdf in objective c for use on the iphone. i found some standard c code and modified it to work, and thought i would provide it here, as up to this point i have used stackoverflow quite a bit but never gave back. you can get it here: http://dl.dropbox...

C Population Count of unsigned 64-bit integer with a maximum value of 15

I use a population count (hamming weight) function intensively in a windows c application and have to optimize it as much as possible in order to boost performance. More than half the cases where I use the function I only need to know the value to a maximum of 15. The software will run on a wide range of processors, both old and new. I a...

Why is NULL/0 an illegal memory location for an object?

I understand the purpose of the NULL constant in C/C++, and I understand that it needs to be represented some way internally. My question is: Is there some fundamental reason why the 0-address would be an invalid memory-location for an object in C/C++? Or are we in theory "wasting" one byte of memory due to this reservation? ...

C socket: problem with connect() and/or accept() between clients. 111: Connection refused

Hello ladies and gents, I'm having a bit of problem with accept(). I have a multiple clients and one server. The clients can connect and communicate just fine with server. But at one point, I need some clients to be directly connected to each other and I'm having a bit of difficulty there. The clients have bunch of threads going on, wher...

A few questions about char pointers.

1- How does this work: char *ptr = "hi"; Now the compiler will put this string in the memory (I'm guessing the stack), and create a pointer to it? Is this is how it works? 2- Also if it is created locally in a function, when the function returns will the memory occupied by the string be freed? 3- Last but not least, why is this not ...

Finding an available network port on the machine

I'm trying to implement a simple FTP server (a variation of the EFTP protocol) in linux. When a client connects and sends the PASV command, the server should respond with a port number, so the client can connect to that port to transmit the file. How can the server choose a port number? Do I need to iterate through all the ports from 102...

comlen function in Java

in c or c++ the function comlen is defined such int comlen(char *p,char *q){ int i=0; while *p && (*p++==*q++) i++; return i; } Is this code equivalent of this function? int comlen(String s,String m){ int i=0; while (i<s.length() && s.charAt(i)==m.charAt(i)){ i++; } return i; } ...

CGI Buffering issue

I have a server side C based CGI code as: cgiFormFileSize("UPDATEFILE", &size); //UPDATEFILE = file being uploaded cgiFormFileName("UPDATEFILE", file_name, 1024); cgiFormFileContentType("UPDATEFILE", mime_type, 1024); buffer = malloc(sizeof(char) * size); if (cgiFormFileOpen("UPDATEFILE", &file) != cgiFormSuccess) { exit(1); } ou...

Wireshark Dissector: How to Identify Missing UDP Frames?

How do you identify missing UDP frames in a custom Wireshark dissector? I have written a custom dissector for the CQS feed (reference page). One of our servers gaps when receiving this feed. According to Wireshark, some UDP frames are never received. I know that the frames were sent because all of our other servers are gap-free. A C...

Constructing a hash table/hash function.

Hi, I would like to construct a hash table that looks up keys in sequences (strings) of bytes ranging from 1 to 15 bytes. I would like to store an integer value, so I imagine an array for hashing would suffice. I'm having difficulty conceptualizing how to construct a hash function such that given the key would give an index into the ar...

Basic Conditional Checking for IF statements in C

Hi there, Can someone please explain what really goes on in this code ? If I put the AND statement, the message wont show if values are less than 0 or greater than 10 ... I think I must use 1 0 logic to work this out right ? I just need someone to briefly explain it please. #include<stdio.h> main(){ puts("enter number"); scanf("%...

Can I do everything in C that C++ and C# and Java can do?

Is it possible to write in C programming language everything that you could write in other languages such as Java, C# or C++. If that's the case why don't schools these days teach C instead of Java? Ok the main reason why I am asking is because I don't want to tie down to a single programming language and platform (.NET and C# or Obj-C ...

IPv6 parsing in C

I wanted to know how i can parse an IPv6 address in 'C' and convert it to a 128 bit value? So a hex address like 1:22:333:aaaa:b:c:d:e:f needs to be converted to its 128 bit equivalent binary. The problem is the IP address could be of the type ::2 and its variant since they are valid IPv6 address. The input is from the keyboard and henc...

C: using clock() to measure time in multi-threaded programs

I've always used clock() to measure how much time my application took from start to finish, as; int main(int argc, char *argv[]) { const clock_t START = clock(); // ... const double T_ELAPSED = (double)(clock() - START) / CLOCKS_PER_SEC; } Since I've started using POSIX threads this seem to fail. It looks like clock() increas...

in C Language what is Ftell() equivalent on delphi.

i am working on C source to translate to delphi but i was stuck on reading files on ftell() function, can you help me find the equivalent function in delphi? ...

understanding the anatomy of file formats and image formats

I am trying to do some research on file formats especially image formats. Information such as header layouts for particular types of image formats and how to parse them using C++. If anyone can point me in the right direction of some good tutorials or books. that would be helpful. thanks [edit] If there are any resources on the general ...

question regarding pointer in c language

char *sample = "String Value"; &sample is a pointer to the pointer of "String Value" is the above statement right? If the above statement right, what is the equivalent of &sample if my declaration is char sample[] = "String Value" ...