Recent questions tagged C

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c - how to convert string to hexadecimal?

I have a string 0xFF, is there any function like atoi which reads that string and save in a uint32_t format? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Rust FFI passing trait object as context to call callbacks on

Okay, I'm trying to achieve the following: C calls into rust rust calls back into c and registers a callback ... idea how to work around that See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Does this invoke undefined behaviour?

Consider the following C program: #include <stdio.h> int main(){ int a =-1; unsigned b=-1; if(a= ... this invoke undefined behavior and why? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Determine priority of a window message

Is there any way to programmatically check the priority of a window messages in its message queue? For example: Some ... be sent first or last? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Creating a FILE * stream that results in a string

I'm looking for a way to pass in a FILE * to some function so that the function can write to it with ... I'm right about the FILE extensibility. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why does write() print before printf() in output redirection?

So I know printf() is higher level than write() and ends up using write(). Printf() is buffered and write( ... () then it is printed first? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What type is NULL?

I'm wondering what type Null is in C. This is probably a duplicate, but I kept getting information about void type ... NULL; } Does that work? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What exactly is -fno-builtin doing here?

So I was reading Hacking the Art of Exploitation and in the book, they use the strcpy() function in ... make sure everything was understood. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - const char pointer assignments

Are the following assignments valid? Or will any of these create problems. Please suggest. const char * c1; const char * ... c2 = c5; c2 = c6; See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Malloc or normal array definition?

When shall i use malloc instead of normal array definition in C? I can't understand the difference between: int a[3 ... (sizeof(int)*sizeof(a)); See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Bitwise shift operators on signed types

I am trying to understand the behavior of bitwise operators on signed and unsigned types. As per the ISO/ ... operator on signed negative int. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Meaning of leading zero in integer literal

I'm studying (ANSI) C by The C Programming Language (2nd Edition). This is a code snippet from 2.10 Assignment ... 0x1? Is 0 before 1 necessary? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why calloc takes two arguments while malloc only one?

IMO one is enough, why does calloc require to split it into two arguments? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Storing and printing integer values greater than 2^64

I am trying to write a program for finding Mersenne prime numbers. Using the unsigned long long type I was able ... and % with this data type. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Posix regular expression non-greedy

Is there a way to use a non-greedy regular expression in C like one can use in Perl? I tried several things, but ... /5.0 (Windows NT HTTP/1.1 See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Integer promotion with the operator <<

Similar to the question Bitshift and integer promotion?, I have a question about integer promotion when using left ... and int 16 bits. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How is printf statement interpreted?

How is the following line interpreted by GCC compiler: printf("HELLO"); I want to know this because when ... printing from the sixth character? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Does a flexible array member increase sizeof a struct?

I have the following kind of code: typedef struct { u32 count; u16 list[]; } message_t; ... message_t* ... compiler work similary in this case? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why should I use, or not use, MSG_CONFIRM?

I am acquainting with BSD sockets, and flicking through the man page of sendto, I bumped into MSG_CONFIRM flag, which is ... it, or not set it? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Removing substring from a string?

I have a C function, which takes a string called 'buffer', and parses it, it will match keywords and use that ... just want to ignore). Thanks, See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to zero out new memory after realloc

What is the best way to zero out new memory after calling realloc while keeping the initially allocated memory intact? ... (); getchar(); } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to check to ensure you have an integer before calling atoi()?

I wish to take an integer as a command line argument, but if the user passes a non-integer string, this ... ensure atoi() will be successful? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Address of array - difference between having an ampersand and no ampersand

I have a struct that looks like this: struct packet { int a; char data[500]; }; typedef struct packet ... have a good explanation for this? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What constitutes asynchronous-safeness

It is said that you should only call asynchronous-safe functions inside a signal handler. My question is, what constitutes ... I guess? Or No? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What's wrong with strcmp?

In the responses to the question Reading In A String and comparing it C, more than one person discouraged ... and recommend strncmp() instead? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - mmap on /proc/pid/mem

Has anybody succeeded in mmap'ing a /proc/pid/mem file with Linux kernel 2.6? I am getting an ENODEV (No ... mmap is setting errno to ENODEV. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How do you determine using stat() whether a file is a symbolic link?

I basically have to write a clone of the UNIX ls command for a class, and I've got almost everything working. ... wrong? Thanks for the help! See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to clear a specific line with NCurses?

How to clear a specific line with NCurses? I need to wipe a line on the screen without redrawing the whole thing. How do I do that? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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