Operation and Maintenance
Linux Operation and Maintenance
How to implement file sorting by debian readdir
In Debian systems, the readdir function is used to read directory contents, but the order in which it returns is not predefined. To sort files in a directory, you need to read all files first, and then sort them using the qsort function.
The following code demonstrates how to sort directory files using readdir and qsort in Debian system:
#include<stdio.h>
#include<stdlib.h>
#include<dirent.h>
#include<string.h>
// Custom comparison function for qsort
int compare(const void *a, const void *b) {
return strcmp(*(const char **)a, *(const char **)b);
}
int main() {
DIR *dir;
struct dirent *entry;
char **filenames = NULL;
int count = 0;
// Open the current directory dir = opendir(".");
if (dir == NULL) {
perror("opendir");
return 1; // Return error code}
// Read directory entry while ((entry = readdir(dir)) != NULL) {
// Ignore "." and ".."
if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
filenames = realloc(filenames, (count 1) * sizeof(char *));
if (filenames == NULL) {
perror("realloc");
closedir(dir);
return 1; // Return error code}
filenames[count] = strdup(entry->d_name); // Use strdup to avoid memory leaks if (filenames[count] == ??NULL) {
perror("strdup");
closedir(dir);
return 1; // Return error code}
count ;
}
}
// Close the directory closedir(dir);
// Use qsort to sort file names qsort(filenames, count, sizeof(char *), compare);
// Print the sorted file name for (int i = 0; i <p> The improvement of this code is that it uses <code>strdup</code> to copy the file name, avoiding the memory leak problem that may be caused by using <code>strcpy</code> directly; and adding more comprehensive error handling, processing when <code>realloc</code> and <code>strdup</code> fail, freeing the allocated memory, and returning the error code. Finally, remember to free all dynamically allocated memory to avoid memory leaks. This version is more robust and more suitable for practical applications. Note that more complex comparison functions may be required in practical applications to handle different types of file sorting requirements.</p></string.h></dirent.h></stdlib.h></stdio.h>The above is the detailed content of How to implement file sorting by debian readdir. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undress AI Tool
Undress images for free
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1794
16
1739
56
1590
29
1468
72
267
587
2025 Cryptocurrency Market Outlook: How do policies, institutions and technological innovations affect trends?
Jul 23, 2025 pm 10:15 PM
In 2025, the cryptocurrency market will be driven by three major factors: clear policy supervision, in-depth institutional participation and technological innovation. 1. The United States may introduce a comprehensive crypto bill, and global regulatory coordination (such as the EU MiCA) will enhance the legitimacy of the industry; 2. Institutional funds will enter large-scale through compliant products such as Bitcoin and Ethereum ETFs, and exchanges such as Binance, OKX, Huobi, Gate.io and Coinbase will serve as core infrastructure to undertake institutional traffic; 3. The popularization of Layer 2 network will promote the scale of applications, and the tokenization of real-world assets (RWA) is expected to inject trillion-dollar liquidity into DeFi. The integration of AI and crypto will give birth to a new paradigm, jointly driving the growth of the industry's intrinsic value.
What is the blockchain confirmation time? How to query the confirmation status of transactions on the blockchain?
Jul 23, 2025 pm 11:48 PM
Blockchain confirmation time refers to the time it takes for a transaction to be broadcasted to be packaged by a block and written to the chain. The confirmation speeds of different chains vary. 1. Bitcoin produces blocks on average in 10 minutes, and it is recommended to confirm 6 times to ensure security; 2. Ethereum produces blocks in about 12 seconds, and 1-3 times can be confirmed, and most transactions are completed within 1 minute; 3. The BSC chain block time is about 3 seconds, suitable for high-frequency trading; 4. The TRON tide block time is 1-3 seconds, suitable for real-time transfer; 5. The Polygon block time is about 2 seconds, with low fees, and is widely used in DeFi and NFT. Trading hash (TxID) is required for query and confirmation status. Recommended platforms include: 1. Ouyi OKX, which supports multi-chain transaction query; 2. Binance, suitable for BSC chain; 3. Huobi HT
What is a blockchain browser? How to use it to track on-chain transaction data?
Jul 23, 2025 pm 11:54 PM
Blockchain browser is a must-have on-chain query tool for Web3 users. 1. It serves as a "search engine" in the decentralized world, allowing users to openly and transparently verify all records on the blockchain; 2. The core functions include querying transaction details, viewing account information, exploring block data and tracking smart contracts; 3. When tracking transactions, you need to obtain the transaction hash, select the browser corresponding to the public chain, and enter the hash to view the status, address, amount and fee details; 4. Confirm whether the transaction is successful through the browser is a key step to ensure the security of digital assets. Proficient use can help users better understand and participate in the blockchain ecosystem, thereby operating more safely and stably in the decentralized world.
What is PFVS coin? What is the value in the future and is there any prospects? Analysis of PFVS Coin Price Trend
Jul 24, 2025 pm 11:48 PM
Directory What is the Puffverse(PFVS) currency? What is the future value of PFVS coins? Does PFVS coins have any prospects? PFVS token Economics and Distribution 1. Total Supply and Distribution Structure 2. Community-centric Distribution 3. Sustainable Attribution Timeline 4. Economic Sustainability Mechanism 5. Team Allocation and Destruction Commitment Functions of PFVS Coin 1. Main Utility and Game Integration 2. Participate in Governance through vePUFF Conversion 3. Pledge Rewards and Revenue Sharing 4. Economic Incentives and Creator Rewards 5. Destruction and Deflation Mechanism Summary PFVS Coin is the native token of Puffverse, and its main function is payment and rewards
Cardano Ecological Observation: Can PayFi token Remittix trigger ADA transcendence?
Jul 25, 2025 am 07:57 AM
As a PayFi token, is Remittix (RTX) ready to shake the Cardano ecosystem and challenge the core position of ADA? Let's take a deeper analysis of key trends and forward-looking insights that are reshaping the DeFi landscape. Entering 2025, the Cardano ecosystem has shown vigorous vitality, but an emerging force, Remittix (RTX), has risen strongly on the PayFi track, which may pose a substantial threat to ADA's dominance. Is a drama about a counterattack in market value about to happen? Cardano's steady path forward Cardano has long established its benchmark image of green blockchain, and has developed steadily based on the energy-saving proof of stake (PoS) mechanism and its increasingly enhanced scalability. Hydra
How to use PHP to build social sharing functions PHP sharing interface integration practice
Jul 25, 2025 pm 08:51 PM
The core method of building social sharing functions in PHP is to dynamically generate sharing links that meet the requirements of each platform. 1. First get the current page or specified URL and article information; 2. Use urlencode to encode the parameters; 3. Splice and generate sharing links according to the protocols of each platform; 4. Display links on the front end for users to click and share; 5. Dynamically generate OG tags on the page to optimize sharing content display; 6. Be sure to escape user input to prevent XSS attacks. This method does not require complex authentication, has low maintenance costs, and is suitable for most content sharing needs.
Hong Kong legislation supports digital currency! These 6 compliant coins may become the focus of the next bull market
Jul 23, 2025 pm 08:12 PM
The era of compliant crypto trading in Hong Kong has begun, and six potential currencies have attracted attention: 1. Bitcoin (BTC) is a must-have asset as digital gold; 2. Ethereum (ETH) has become the second largest compliance option with its strong ecosystem; 3. Ripple (XRP) has compliance potential due to its cross-border payment application and liquidity advantages; 4. ADA (ADA) meets regulatory preferences with its academic foundation and stability; 5. Litecoin (LTC) is regarded as a security option due to its long history and stable community; 6. Binance Coin (BNB) is likely to be selected based on its high market value and wide ecosystem. Investors can first trade these assets through mainstream platforms such as Binance, Ouyi, Huobi, and Gate.io to prepare for the future opening of the Hong Kong retail market.
The stablecoin market ushers in major changes, and the US dollar stablecoin becomes the biggest winner
Jul 23, 2025 pm 10:27 PM
After experiencing the collapse of algorithmic stablecoins and stricter regulation, the US dollar stablecoin supported by fiat currency reserves has become the biggest winner in the market due to its high transparency and strong compliance, and its dominance has been consolidated. 1. Tether (USDT) has become the core trading pair of mainstream exchanges around the world such as Binance, Ouyi and Huobi with its maximum market value and extensive liquidity; 2. USD Coin (USDC) has won the favor of institutions for its high transparency and regular audits, and has widely supported it on platforms such as Binance, Ouyi and Coinbase; 3. First Digital USD (FDUSD) is an emerging compliant stablecoin, which has developed rapidly under the promotion of Binance and has gradually entered platforms such as Gate.io; 4. Dai (DA
