1. Article purpose[edit source]
This article provides the basic information needed to start using the Linux tool: ltrace[1].
2. Introduction[edit source]
The following table provides a brief description of the tool, as well as its availability depending on the software packages:
: this tool is either present (ready to use or to be activated), or can be integrated and activated on the software package.
: this tool is not present and cannot be integrated, or it is present but cannot be activated on the software package.
| Tool | STM32MPU Embedded Software distribution | STM32MPU Embedded Software distribution for Android™ | ||||||
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| Name | Category | Purpose | Starter Package | Developer Package | Distribution Package | Starter Package | Developer Package | Distribution Package |
| ltrace | Tracing tools | ltrace[1] is used to display the calls to shared libraries made by a userspace application. ltrace is a userspace application. Its use is very similar to strace. |
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3. Installing the trace and debug tool on your target board[edit source]
3.1. Using the STM32MPU Embedded Software distribution[edit source]
ltrace is not part of the standard STM32MPU Embedded Software distribution image.
3.1.1. Distribution Package[edit source]
To include ltrace in your Distribution Package image build, please follow steps below:
- Add ltrace package for the image building
cd <your_Distribution_Package_root_dir>
echo 'IMAGE_INSTALL_append += "ltrace"' >> layers/meta-st/meta-st-openstlinux/recipes-st/images/st-image-weston.bbappend
- Rebuild your full image
bitbake <full_image_name> # Needed to include ltrace into the final image rootfs
- Reload the new image on your board: see Flashing the built image
4. Getting started[edit source]
To use ltrace, there are two main methods:
- by giving, as parameter, the name of program for which you want to list dynamic library calls, and its arguments if required:
ltrace <Program> [ARGS]
- As example:
ltrace weston-simple-egl __libc_start_main(0x11a90, 1, 0xbec45d04, 0x131f0 <unfinished ...> memset(0xbec456f8, 0, 72, 0x11a90) = 0xbec456f8 memset(0xbec45754, 0, 68, 0xbec45740) = 0xbec45754 wl_display_connect(0, 250, 32, 0xbec45750) = 0x26150 wl_proxy_marshal_constructor(0x26150, 1, 0x24e90, 0) = 0x2a268 wl_proxy_add_listener(0x2a268, 0x132e0, 0xbec456f8, 0) = 0 wl_display_roundtrip(0x26150, 0x132e0, 0xbec456f8, 0 <unfinished ...> strcmp(0x2a404, 0x133e8, 1, 0x2a404) = 0 wl_proxy_marshal_constructor_versioned(0x2a268, 0, 0x24ed8, 1) = 0x2b070 strcmp(0x2a49c, 0x133e8, 2, 0x2a49c) = 16 strcmp(0x2a49c, 0x133f8, 115, 0x635f6c77) = -3 ...
- by giving, as parameter, the PID of the process to be studied:
ltrace -p <PID>
Note: <PID> value can be replace by `pidof <process_name>`
- As example:
weston-simple-egl & ltrace -p `pidof weston-simple-egl` has EGL_EXT_buffer_age and EGL_EXT_swap_buffers_with_damage glGetShaderiv(1, 0x8b81, 0xbee14260, 0) = 0 glCreateShader(0x8b31, 0x8b31, 256, 1) = 2 glShaderSource(2, 1, 0xbee1425c, 0) = 0x1a96f0 glCompileShader(2, 0, 154, 0xbee14260) = 1 glGetShaderiv(2, 0x8b81, 0xbee14260, 0) = 0 glCreateProgram(2, 2, 256, 1) = 3 glAttachShader(3, 1, -1, 1) = 0 glAttachShader(3, 2, 0x8b30, 1) = 0 glLinkProgram(3, 0x8dd9, 0x8b31, 1) = 0x285234 glGetProgramiv(3, 0x8b82, 0xbee14698, 0) = 0 glUseProgram(3, 3, 256, 1) = 1 glBindAttribLocation(3, 0, 0x13884, 1) = 1 glBindAttribLocation(3, 1, 0x13888, 0) = 1 glLinkProgram(3, 0x1388e, 0, 0x1b9090) = 1 ... killall weston-simple-egl
5. To go further[edit source]
Other options can be set. For details, please refer to the manual page[2].
6. References[edit source]
- Useful external links
| Document link | Document Type | Description |
|---|---|---|
| ltrace linux.die.net | Standard | linux.die.net |
| ltrace wikipedia.org | Standard | wikipedia.org |
| ltrace tutorial | User Guide | go4expert.com |
| ltrace training
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Training | ellexus.com |