10 More Discussions You Might Find Interesting
1. BSD
I'm new to kernels and C, and I am tinkering around trying to understand OpenBSD's secure memory management. I'm stumped on a couple points.
I've read up on malloc() which was apparently modified years ago to allocate memory using mmap. First question, that would be this here, right?
... (4 Replies)
Discussion started by: dcicc
4 Replies
2. Emergency UNIX and Linux Support
I want to know whether this is possile or ever been tried out.
I want to obtain a chuck of memory using mmap()
I do it so :
n = mmap(0, 8000, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
And hold on to that memory, when a process requests for memory, some memory is... (2 Replies)
Discussion started by: xerox
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3. UNIX for Advanced & Expert Users
Hi
I want to lock or prevent a portion of memory which I allocated. So I tried MLOCK, MPROTECT and some like this. But all these functions works only on page border. Can I know why that so.
Is that possible to protect a portion of memory which is in middle of the page.
Example.
int A;
... (1 Reply)
Discussion started by: jionnet
1 Replies
4. Programming
hai,
How do we map 'n' number of files into memory by using mmap system call??
Thanks in advance...... (5 Replies)
Discussion started by: andrew.paul
5 Replies
5. Homework & Coursework Questions
Descriptions:
Develop a program that uses mmap() to map a file to memory space. Prepare such a file by yourself and do the follows.
<LI class=MsoNormal>Display the content of the file after mapping; <LI class=MsoNormal>Output how many digits included in the file; <LI class=MsoNormal>Replace... (1 Reply)
Discussion started by: gokult
1 Replies
6. Programming
how to use mmap() to map a file to memory space. Do you have any simple program???? Because I have to implement lot of concepts into it. (5 Replies)
Discussion started by: gokult
5 Replies
7. UNIX for Dummies Questions & Answers
how to use mmap() to map a file to memory space. Do you have any simple program???? Because I have to implement lot of concepts into it. (3 Replies)
Discussion started by: gokult
3 Replies
8. Solaris
Dear Experts,
i have a problem related to mmap(), when i run my program on sun for 64 bit which is throwing SIGBUS when it encounters mmap() function, what is the reason how to resolve this one, because it is working for 32 bit.
with regards,
vidya. (2 Replies)
Discussion started by: vin_pll
2 Replies
9. UNIX for Advanced & Expert Users
I'm using select() to monitor multiple file descriptors (inet sockets) in application. But this application must also collaborate with other applications on the same host via shared memory (mmap'ed file) due to performance reasons. How can I become notification that mmaped memory is changed or... (1 Reply)
Discussion started by: Hitori
1 Replies
10. HP-UX
We recently have been seeing the following type of error on our development server. Being somewhat new to HP-UX I was hoping to get some insight. Here is what I have found.
I have been doing some research.
/usr/lib/dld.sl: Call to mmap() failed - TEXT /u07/mdev/lib/libCLEND.sl... (2 Replies)
Discussion started by: scotbuff
2 Replies
MMAP2(2) Linux Programmer's Manual MMAP2(2)
NAME
mmap2 - map files or devices into memory
SYNOPSIS
#include <sys/mman.h>
void *mmap2(void *addr, size_t length, int prot,
int flags, int fd, off_t pgoffset);
DESCRIPTION
This is probably not the system call that you are interested in; instead, see mmap(2), which describes the glibc wrapper function that
invokes this system call.
The mmap2() system call provides the same interface as mmap(2), except that the final argument specifies the offset into the file in
4096-byte units (instead of bytes, as is done by mmap(2)). This enables applications that use a 32-bit off_t to map large files (up to
2^44 bytes).
RETURN VALUE
On success, mmap2() returns a pointer to the mapped area. On error, -1 is returned and errno is set appropriately.
ERRORS
EFAULT Problem with getting the data from user space.
EINVAL (Various platforms where the page size is not 4096 bytes.) offset * 4096 is not a multiple of the system page size.
mmap2() can also return any of the errors described in mmap(2).
VERSIONS
mmap2() is available since Linux 2.3.31.
CONFORMING TO
This system call is Linux-specific.
NOTES
On architectures where this system call is present, the glibc mmap() wrapper function invokes this system call rather than the mmap(2) sys-
tem call.
This system call does not exist on x86-64.
On ia64, the unit for offset is actually the system page size, rather than 4096 bytes.
SEE ALSO
getpagesize(2), mmap(2), mremap(2), msync(2), shm_open(3)
COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the
latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
Linux 2017-09-15 MMAP2(2)