Recent questions tagged C

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c - Difference between uninitialized and null pointer

Is there any difference between null pointer and uninitialized pointer? This question was asked in one of the ... difference that they have? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - reading lines using fscanf

hi i have a file which contains following lines: wwa weweweof ewewe wdw: 1 11 ms <1 ms <1 ms 174. ... the above else-if statements accordingly? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Is malloc() initializing allocated array to zero?

Here is the code I'm using: #include <stdio.h> #include <stdlib.h> int main() { int *arr; int sz = ... memory to zero. Why is this happening? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - I need a pixel-perfect triangle fill algorithm to avoid aliasing artifacts

I'm assisting someone with user interface code to visualise a mathematical image analysis. During this process we'll ... accurate to one pixel. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - gotoxy() implementation for Linux using printf

I was looking for a substitute of gotoxy() for gcc compiler and found this - void gotoxy(int x,int y) { ... can find about such uses of printf. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to encrypt data using RSA, with SHA-256 as hash function and MGF1 as mask generating function?

I was doing some experiments with cryptography. Now I have the public key of receiver and i want to encrypt some data ... . How can I do it ? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why do we need a condition check before pthread_cond_wait

I am trying to learn basics of pthread_cond_wait. In all the usages, I see either if(cond is false) ... output thread to print it. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Can a "container_of" macro ever be strictly-conforming?

A commonly-used macro in the linux kernel (and other places) is container_of, which is (basically) defined as ... my answer to this question. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to find EOF through fscanf?

I am reading matrix through file with the help of fscanf(). How can i find EOF? Even if i try to find EOF after ... EOF . how can it be solved? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Hamming weight based indexing

Assume we have a integer of bitsize n=4; The problem I am describing is how you would go about indexing a ... you could go about doing that. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to check the value of errno?

I am using a system call and in case it fails, I need to do different things for different errnos. I need to ... in order to test the errno? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - ftello/fseeko vs fgetpos/fsetpos

What is the difference between ftello/fseeko and fgetpos/fsetpos? Both seem to be file pointer getting/setting ... applicable to ftello/fseeko. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Link glibc statically but some other library dynamically with GCC

I need to statically link glibc to my project, because the target platform supports only a very old one ( but ... /bin/ld: cannot find -lgcc_s See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to upload 32 bit image to server-side pixmap

I'm trying to create server-side RGBA pixmap from client side buffer. CreatePixmap & CreateImage work ok for 32 and ... (display, &ev); } } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Calculate broadcast address from ip and subnet mask

I want to calculate the broadcast address for: IP: 192.168.3.1 Subnet: 255.255.255.0 = 192.168.3.255 in C. I ... example of how to do it in C? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Find out whether a pointer is pointing at the stack, heap or program text?

Is there a way to find out whether a pointer is pointing at a location in: the stack the heap or the ... far: Checking if something was malloced See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Always check malloc'ed memory?

I often catch myself doing the following (in non-critical components): some_small_struct *ptr=(some_small_struct *) ... -Of-Memory) conditions See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - how to return a string array from a function

char * myFunction () { char sub_str[10][20]; return sub_str; } void main () { char *str; str ... :return from incompatible pointer type thanks See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Unzip a zip file using zlib

I have an archive.zip which contains two crypted ".txt" files. I would like to decompress the archive in ... files with my data uncompressed. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Tracing/profiling instructions

I'd like to statistically profile my C code at the instruction level. I need to know how many additions, ... profiling tools which enable this? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to pass arguments to processes created by fork()

I want to create copies of a process using fork() in C. I cant figure out how to pass arguments to the ... a unique value to new processes. } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What are the reasons to check for error on close()?

Note: Please read to the end before marking this as duplicate. While it's similar, the scope of what I' ... configurations) they might be seen. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why volatile works for setjmp/longjmp

After invoking longjmp(), non-volatile-qualified local objects should not be accessed if their values could have changed since ... buf, 1 ); } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How do I get the lower 8 bits of an int?

Lets say I have an int variable n = 8. On most machines this will be a 32 bit value. How can I only get the ... each bit to find out what it is? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - OpenCV cvFindContours - how do I separate components of a contour

I've been playing around with OpenCV and with alot of trial and error have managed to learn how to ... advice would be greatly appreciated. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is the meaning of "%-*.*s" in a printf format string?

#define FMT "%-*.*s e = %6ld, chars = %7ld, stat = %3u: %c %c %c %c " This macro is passed into the printf function. What does %-*.*s mean? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Meaning of double underscore in the beginning

In the standard library (glibc) I see functions defined with leading double underscores, such as __mmap in sys/ ... , it declares only __mmap. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - printf slows down my program

I have a small C program to calculate hashes (for hash tables). The code looks quite clean I hope, but ... programs, switch to another TTY! See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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