Why May CreateFileMapping() Throw Error 87?

Are you tired of dealing with the frustration of CreateFileMapping() throwing error 87? You’re not alone! This common issue can be a major roadblock for developers, but fear not, dear reader, for we’re about to dive into the world of file mapping and uncover the reasons behind this pesky error.

What is CreateFileMapping()?

Before we dive into the nitty-gritty of error 87, let’s take a step back and understand what CreateFileMapping() actually does. This API function is used to create a file mapping object, which allows multiple processes to share data by mapping a file into memory. Think of it like a shared workspace where multiple applications can collaborate and exchange data seamlessly.

The Problem: Error 87

So, what’s the deal with error 87? Why does it keep popping up and ruining our day? Error 87, also known as ERROR_INVALID_PARAMETER, typically occurs when one or more of the input parameters passed to CreateFileMapping() are invalid. But what does that even mean?

Invalid Parameter: The Culprit Behind Error 87

The primary cause of error 87 is passing incorrect or invalid parameters to CreateFileMapping(). This can happen due to a variety of reasons, including:

• Invalid file handle: If the file handle passed to CreateFileMapping() is invalid, you can bet your bottom dollar that error 87 will rear its ugly head. Make sure the file handle is valid and points to a file that exists.
• Insufficient privilege: If the calling process lacks the necessary privilege to create a file mapping, error 87 will be thrown. Ensure that the process has the required permissions to create a file mapping.
• Incorrect security attributes: If the security attributes passed to CreateFileMapping() are invalid or incomplete, error 87 will occur. Double-check the security attributes to ensure they’re correct.
• Invalid mapping name: If the mapping name passed to CreateFileMapping() is invalid or already in use, error 87 will be thrown. Choose a unique and valid mapping name to avoid this issue.

Other Possible Causes of Error 87

While invalid parameters are the primary cause of error 87, there are other potential culprits to watch out for:

1. System resource limits: If the system is low on resources, such as memory or handles, CreateFileMapping() may fail and return error 87.
2. File system limitations: Certain file systems, like FAT32, have limitations on file size and mapping. Make sure the file system can support the file mapping you’re trying to create.
3. Third-party software interference: Sometimes, third-party software can interfere with the CreateFileMapping() function, causing error 87. Try closing other applications or services that might be causing the issue.

How to Fix Error 87: A Step-by-Step Guide

Now that we’ve covered the possible causes of error 87, let’s dive into the solution! Follow these steps to troubleshoot and fix error 87:

Step 1: Verify the File Handle

HANDLE hFile = CreateFileW("example.txt", GENERIC_READ | GENERIC_WRITE, 
                             FILE_SHARE_READ | FILE_SHARE_WRITE, 
                             NULL, CREATE_ALWAYS, 
                             FILE_ATTRIBUTE_NORMAL, NULL);
if (hFile == INVALID_HANDLE_VALUE) {
    // Handle error: unable to open file
}

Step 2: Check Security Attributes

PSECURITY_ATTRIBUTES pSA = new SECURITY_ATTRIBUTES();
pSA->nLength = sizeof(SECURITY_ATTRIBUTES);
pSA->lpSecurityDescriptor = NULL;
pSA->bInheritHandle = TRUE;

Step 3: Validate the Mapping Name

TCHAR szMappingName[MAX_PATH] = TEXT("MyMappingName");
if (!_tcslen(szMappingName) || _tcschr(szMappingName, TEXT('\0')) != NULL) {
    // Handle error: invalid mapping name
}

Step 4: Verify System Resources

SYSTEM_INFO si;
GetSystemInfo(&si);
if (si.dwNumberOfPages * si.dwPageSize / 1024 < 1048576) {
    // Handle error: insufficient system resources
}

Step 5: Check File System Limitations

ULONGLONGFileSize = GetFileSize(hFile, NULL);
if (FileSize > 0xFFFFFFFF) {
    // Handle error: file size exceeds file system limitations
}

Step 6: Verify Third-Party Software Interference

// Close other applications or services that might be causing the issue

Best Practices to Avoid Error 87

To avoid error 87 in the future, follow these best practices:

• Validate input parameters: Always validate the input parameters passed to CreateFileMapping() to ensure they're correct and valid.
• Use secure coding practices: Follow secure coding practices, such as input validation and error handling, to prevent common errors like error 87.
• Monitor system resources: Keep an eye on system resources, such as memory and handles, to avoid resource-related issues.
• Test thoroughly: Thoroughly test your application to catch errors like error 87 before they become a problem.

Conclusion

Error 87 can be a frustrating issue, but by understanding the causes and following the steps outlined in this article, you can troubleshoot and fix the problem. Remember to validate input parameters, use secure coding practices, monitor system resources, and test thoroughly to avoid error 87 in the future. Happy coding!

Cause of Error 87	Solution
Invalid file handle	Verify the file handle is valid and points to a file that exists.
Insufficient privilege	Ensure the process has the required permissions to create a file mapping.
Incorrect security attributes	Double-check the security attributes to ensure they're correct.
Invalid mapping name	Choose a unique and valid mapping name.
System resource limits	Monitor system resources, such as memory and handles, to avoid resource-related issues.
File system limitations	Ensure the file system can support the file mapping you're trying to create.
Third-party software interference	Close other applications or services that might be causing the issue.

By following this comprehensive guide, you'll be well on your way to resolving error 87 and creating a seamless file mapping experience for your users.

Frequently Asked Question

CreateFileMapping is a powerful function in Windows programming, but sometimes it can throw error 87, leaving you scratching your head. Don't worry, we've got you covered! Here are the top reasons why CreateFileMapping might throw error 87: